Mask data generation method and mask data generation program

Abstract

A mask data generation method including: calculating first evaluation value of projection image based on first mask data in which first value or second value different from first value is set for each of a plurality of unit elements that constitute 2-dimensional grid; generating second mask data by changing value of first unit element to which first value is set to second value and by changing value of second unit element which is disposed close to first unit element on 2-dimensional grid and to which second value is set to first value, among the plurality of unit elements included in the first mask data; calculating second evaluation value of projection image based on the second mask data; and comparing the first evaluation value and the second evaluation value and selecting either the first mask data or the second mask data as output mask data based on the comparison result.

The invention claimed is: 
     
       1. A mask data generation method comprising:
 calculating a first evaluation value of a projection image based on first mask data in which a first value or a second value different from the first value is set for each of a plurality of unit elements that constitute a 2-dimensional grid; 
 generating second mask data by changing a value of a first unit element to which the first value is set to a second value and by changing a value of a second unit element which is disposed close to the first unit element on the 2-dimensional grid and to which the second value is set to the first value, among the plurality of unit elements included in the first mask data; 
 calculating a second evaluation value of the projection image based on the second mask data; and 
 comparing the first evaluation value and the second evaluation value and selecting either the first mask data or the second mask data as output mask data on the basis of the comparison result. 
 
     
     
       2. The mask data generation method according to  claim 1 , wherein a change of a value of the first unit element to the second value and a change of a value of the second unit element to the first value are performed with respect to a plurality of the first unit elements and a plurality of the second unit elements. 
     
     
       3. The mask data generation method according to  claim 1 , wherein the output mask data is set as the first mask data,
 the second evaluation value is set as the first evaluation value when the selected output mask data is the second mask data, and 
 generation of the second mask data, calculation of the second evaluation value, and selection of the output mask data are repeated for a plurality of times. 
 
     
     
       4. The mask data generation method according to  claim 1 , wherein the second unit element is disposed close to the first unit element on the 2-dimensional grid. 
     
     
       5. The mask data generation method according to  claim 1 , wherein the second unit element is within twice a distance of a design rule of the first mask data on the 2-dimensional grid with respect to the first unit element. 
     
     
       6. The mask data generation method according to  claim 1 , wherein a technique of calculating the first evaluation value is same as that of calculating the second evaluation value. 
     
     
       7. The mask data generation method according to  claim 6 , wherein, in the same technique, either the first evaluation value or the second evaluation value is calculated on the basis of a difference between an intensity distribution of a reference image and an intensity distribution of the projection image of the first mask data or the second mask data. 
     
     
       8. The mask data generation method according to  claim 1 , wherein the first value and the second value are value related to amplitude transmittance or amplitude reflectance of light in a mask, and the second value is −1 times the first value. 
     
     
       9. The mask data generation method according to  claim 1 , wherein the first value and the second value are values related to amplitude transmittance or amplitude reflectance of light in a mask, and
 one of the first value and the second value is 0. 
 
     
     
       10. The mask data generation method according to  claim 2 , wherein the output mask data is set as the first mask data,
 the second evaluation value is set as the first evaluation value when the selected output mask data is the second mask data, and 
 generation of the second mask data, calculation of the second evaluation value, and selection of the output mask data are repeated for a plurality of times. 
 
     
     
       11. The mask data generation method according to  claim 10 , wherein the second unit element is disposed close to the first unit element on the 2-dimensional grid. 
     
     
       12. The mask data generation method according to  claim 11 , wherein the second unit element is within twice a distance of a design rule of the first mask data on the 2-dimensional grid with respect to the first unit element. 
     
     
       13. The mask data generation method according to  claim 12 , wherein a technique of calculating the first evaluation value is same as that of calculating the second evaluation value. 
     
     
       14. The mask data generation method according to  claim 13 , wherein, in the same technique, either the first evaluation value or the second evaluation value is calculated on the basis of a difference between an intensity distribution of a reference image and an intensity distribution of the projection image of the first mask data or the second mask data. 
     
     
       15. The mask data generation method according to  claim 14 , wherein the first value and the second value are value related to amplitude transmittance or amplitude reflectance of light in a mask, and
 the second value is −1 times the first value. 
 
     
     
       16. The mask data generation method according to  claim 14 , wherein the first value and the second value are values related to amplitude transmittance or amplitude reflectance of light in a mask, and
 one of the first value and the second value is 0. 
 
     
     
       17. A mask data generation program configured to cause a data processing device including a computer to perform:
 storing first mask data to which a first value or a second value different from the first value is set for each of a plurality of unit elements that constitute a 2-dimensional grid in a storage region; 
 calculating a first evaluation value of a projection image based on the first mask data; 
 generating second mask data by changing a value of a first unit element to which the first value is set to a second value and by changing a value of a second unit element which is disposed close to the first unit element on the 2-dimensional grid and to which the second value is set to the first value, among the plurality of unit elements included in the first mask data; 
 calculating a second evaluation value of a projection image based on the second mask data; and 
 comparing the first evaluation value and the second evaluation value and selecting either the first mask data or the second mask data as output mask data on the basis of the comparison result. 
 
     
     
       18. The mask data generation program according to  claim 17 , wherein a change of a value of the first unit element to the second value and a change of a value of the second unit element to the first value are performed with respect to a plurality of the first unit elements and a plurality of the second unit elements. 
     
     
       19. The mask data generation program according to  claim 17 , wherein the output mask data is set as the first mask data,
 the second evaluation value is set as the first evaluation value when the selected output mask data is the second mask data, and 
 generation of the second mask data, calculation of the second evaluation value, and selection of the output mask data are repeated for a plurality of times. 
 
     
     
       20. The mask data generation program according to  claim 17 , wherein the second unit element is disposed close to the first unit element on the 2-dimensional grid. 
     
     
       21. The mask data generation program according to  claim 17 , wherein the second unit element is within twice a distance of a design rule of the first mask data on the 2-dimensional grid with respect to the first unit element. 
     
     
       22. The mask data generation program according to  claim 18 , wherein the output mask data is set as the first mask data,
 the second evaluation value is set as the first evaluation value when the selected output mask data is the second mask data, and 
 generation of the second mask data, calculation of the second evaluation value, and selection of the output mask data are repeated for a plurality of times. 
 
     
     
       23. The mask data generation program according to  claim 22 , wherein the second unit element is disposed close to the first unit element on the 2-dimensional grid. 
     
     
       24. The mask data generation program according to  claim 23 , wherein the second unit element is within twice a distance of a design rule of the first mask data on the 2-dimensional grid with respect to the first unit element.